COMMUNITY FORUM

Hot water heating system with a slow leak. How can we find the leak?

We have lived here about 11 years and the last 2 winters we have seen the lbs. of water go down and had to add water more frequently. Does the humidity level in the basement affect this system. We cannot find any leaks.

Hot water boilers are sealed systems, if you loose pressure then there is a leak.
Remember that the water is hot and if the leak is really small the water will evaporate and not leave a noticeable leak, however it will cause corrosion to form around the leaking area.
Look around the boiler and surrounding piping and valves for suspect areas.
The leak could also be at a joint under the house or in a wall, however this is less likely.
One concern I have is you stated you have to add water, this unit should have a reducing valve that automatically feeds the boiler to 12lbs of pressure.
If you have to add water with the handle on the reducing valve then it is defective.
Feel free to inspect and let us know what you find.